Generalized Pattern Search Methods for control of stable, unstable and integrating systems with unknown delay under step input

Abstract

A number of different analytical and numerical methods have previously been proposed to identify and control systems with unknown delay. The methods have been based on the Smith Predictor for the stable case and on modified Smith predictor, for the unstable and integrating case. Among the proposed optimization techniques, the pattern-search-based method besides its computational advantage, provides better accuracy compared to other methods. However, the response of the methods under step input in some case is deficient. This paper presents an improved Generalized Pattern Search Method (GPSM) based optimization technique, where new updates ways are proposed. The proposed GPSM algorithm uses a simple structure based on the feedback of fitness value in the process. It provides better performance for delay identification and a reference tracking. Comparisons with existing methods for delay estimation are presented using both synthetic and experimental data under various conditions. The proposed scheme offers higher accuracy, and also eliminates the need for users to manually tune the control parameters of Pattern Search Methods.